Process of obtaining polar-type corrosion-inhibiting agents soluble in petroleum lubricating oils



y 1947- J. E. SHIELDS ET AL 2,421,040

PROCESS OF OBTAINING POLAR-TYPE CQRROSION-INHIBITING AGENTS SOLUBLE IN PETROLEUM LUBRICATING OILS Filed June 18, 1942 o/pefra/eum of peflo/eum V Mixer 0011c. 2 4 #42 Mini-insoluble L 4M ,& Acid-soluble lqyer Hi0 W056 J'fi/l 1 y l. we?

mm 01 flmy/ #2 #10060! Y libs/2 wafer & Washer Q M515 wafer Patented May 27, 1947- PROCESS OF OBTAINING POLAR-TYPE COR- ROSION-INHIBITING AGENTS SOLUBLE IN PETROLEUM LUBRICATING OILS James E. Shields and Edward V. Reilly, Niagara Falls, N. Y., assignors to Alex Corporation, New York, N. Y.,' a corporation of New York Application June 18, 1942, Serial No. 447,594

8 Claims.

This invention relates to the provision of compositions and substances for use on surfaces of corrodible metal parts to lubricate and to protect the same against corrosion, and is particularly concerned with the provision of an improved oilsoluble corrosion-inhibiting compound, which compound is adapted to be blended with a lubricating oil to provide a combined lubricant and anti-corrosive composition.

An object of the present invention is the provision of an improved oil-soluble, non-volatile, corrosion-inhibiting agent of the polar type. Another object of the invention is the provision of an oil-soluble corrosion-inhibiting and lubricityincreasing agent of the polar type, which agent is non-volatile, has a low viscosity and low pour point, and is additionally characterized by a high degree of potency in preventing corrosion of corrodible metal surfaces. A further inventive object is the provision of a polar-type, nonvolatile, corrosion-inhibiting and lubricity-increasing agent having low viscosity aiid low pour point, which agent is. adapted to be blended with-specifically dissolved in--'-a light lubricating oil to yield an improved corrosion-preventing light lubricating oil composition characterized by an extremely low pour point. Other inventive objects will be apparent from a consideration of the following description:

In' U. S. Patents Nos. 1,690,769 and 1,768,523 to Arthur W. Burwell there is described a process for producing both saponifiable and unsaponifiable oxidized petroleum hydrocarbon compounds by controlled, liquid-phase partial oxidation of a petroleum'fraction with air or other oxygencontaining gas. Said process involves the steps of passing the air through the liquid or liquefied petroleum fraction at an elevated temperature above 100 C. (e. g., at about 140 C.) and at a superatmospherlc pressure (e. g., about 250 lbs./sq.,in.), preferably in the presence of an exciter of oxidation, until a reaction mixture containing both saponifiable (acidic) and unsaponifiable (substantially neutral) oxidized compounds results, and thereafter separating the saponifiables from the unsaponifiables of said reaction mixture.

The invention is based upon the discovery that from mixtures of oxidized petroleum hydrocarbuns-more especially mixtures of unsapcnifiable, substantially neutral, predominately aliphatic and saturated oxidized petroleum hydrocarbons,-obtained by the controlled liquidphase partial oxidation of a petroleum fraction by the above-described Burwell process, there may be extracted certain products-having unique properties a polar-type corrosion-inhibiting agents which products are miscible in various oils including hydrocarbon lubricating oils to which latter they contribute added lubricity. Said mixtures of unsaponiflable, substantially neutral, predominately aliphatic and saturated oxidized petroleum hydrocarbons" substantially consist of aliphatic alcohols, aliphatic ketones, aliphatic into-alcohols; and neutral esters and lactones of high molecular weight predominately saturated aliphatic carboxylic acids (1. e., neutral esters and lactones of the so-called "Alox acids), together with some hydrocarbons of the starting material which had escaped oxidation.

The petroleum fraction used as starting material oi the oxidation procedure productive of the aforesaid oxygenated compounds mixture may be a normally liquid fraction or it may be a normally solid, 1. e., waxy, fraction such as parafin wax or amorphous green wax ("Sharpies wax) preferably, however, said mixture is composed of the unsaponifiables from the oxidation, by the -Burwell process, of a plurality of diiier= ent petroleum fractions including waxes and oils, e. g., of paraflln wax and Sharples wax," or of paramn wax and a normally liquid distillate, or

of paraflin wax, "Sharples Wax" and a normally or the like (but not a, solvent of high aromatic content), and the' so-diluted mixture is treated with concentrated sulphuric acid, in an amount corresponding to about 145 pounds of the 00118621 trated acid for each pounds of the urn saponifiables mixture beforedilution, by slowly adding the acid, a portion at a time, to the diluted unsaponifiables mixture, vigorously agitated and gredients oi the .unsaponifiables mixture, and (2) a subnatant layer which is a solution in concentrated' sulphuric acid of oxygenated compounds and possibly compounds resulting from reaction with sulphuric acid. The desired products are present in the sulphuric acid solution which constitutes the .subnatant layer (2). The latter is separated from the supernatant layer (1) and is mixed (agitated) with about an equal quantity 01' water. The aqueous material is allowed to settle, and, after a period of settling, the resulting bottom aqueous acidic layer containing dilute, sulphuric acid and any compounds soluble in the dilute acid, is discarded. 'The retained portion (2a) of the subnatant layer (2) is then worked up, preferably in the following manner:

The retained water (and dilute acid) -insoluble portion (2a) is mixed with about an equal volume of amyl alcohol (or, a mixture of amyl alcohols such as the commercial product known as Pentasol," or other higher alcohol of poor water solubility such as hexyl or octyl r decyl alcohol, or xylene or toluene or mixture thereof with a higher alcohol, e. g., with amyl alcohol), is washed with hot lime water (or sodium hydroxide solution or sodium carbonate solution or equivalent aqueous neutralizing agent) and then is washed a plurality of times with hot water. The thoroughly washed, substantially neutral material is then distilled to a final temperature or about 375 F. to remove all diluent, e. g., alcohol. The still residue constitutes the desired final product. The yield usually. amounts to about 40-42% by weight of the "unsaponifiables mixture" from which it is derived.

Alternatively, the retained (that is, water-insoluble) portion (2a) is mixed with about an equal volume of petroleum naphtha and then treated with excess hydrated lime, under vigorous agitation, until it is neutral, Calcium sulphate and excess hydrated. lime are filtered out, and the filtrate is distilled to a final temperature of about 400, F; to remove all solvent, the still residue constituting the desired final product. The yield is substantially the same as that from the amyl alcohol method above described.

The supernatant layer (1) may be suitably worked up to recover the solvent (i. e., the naphtha, or equivalent) by washing same with hot water, and distilling the washed material at a temperature to distill off the solvent, treating the condensed distillate with a suitable alkaline neutralizing agent (e. g., NaOH) and recycled. Tile still residue may be discarded, or again oxid ed.

As will be understood, the amyl alcohol (or naphtha or other diluent) used in working up the subnatant layer (2) likewise may be collected, neutralized with a suitable alkaline neutralizing agent (e. g., NaOH) and recycled.

While xylene or toluene is operable as a substitute for amyl alcohol inthe above described working up of the acid-soluble layer (2), the latter is the preferred agent because it separates from water better than the xylene or toluene does.

In the accompanying drawing the single figur is a flow chart of thecomplete process, illustrating the use of amyl alcohol in the working up of the acid-soluble subnatant layer (2) The unsaponifiables mixture" used in this process may, for example, be one or another of the following: a

I. The unsaponifiable bodies recovered from a mass produced by the oxidation of a paraiiinic blowing oil (e. 8., "Triton No. 20'') by the Burwell rocess. The final product irom this startin -material is dark in color; liquidat normal room 1. Dark color.

2. M. P.--95 F.

3. Acid number-0.0 to 0.5.

4. Saponiflcation number25 to 35. 5. Misclble in lubricating oil.

6. Sulphur content-about 0.6%.

III. The unsaponiflable bodies recovered from a mass produced by the oxidation, ,by the Burwell process, of a mixture of 2 parts by weight of crude scale wax (paraflin wax) and 1 part by.weight of "Sharples wax (amorphous green wax). The final product from this starting material has the following characteristics:

1. Dark color.

2. M. P.---100 F.

3. Acid number-0.0 to 0.5.

4. Saponification number-30 to 40. 5. Miscible in lubricating oil.

6. Sulphur content--00 to 0.5%,

IV. 375 parts by weight oi! the unsaponifiable bodies recovered from the mass produced by the oxidation, by the Burwell process, of parailinic blowing oil (e. g.,' Triton N0. 20") mixed with parts by weight of the unsaponifiable bodies recovered from they mass produced by the oxida-' tion, by the Burwell process, of a mixture of crude scale wax and A; "Sharples wax. The final product from this starting material has the following characteristics:

. Dark color.

. M. P.--75-85 F.

. Acid number-about 0.5.

. Saponification number--about 21.9. Miscible in lubricating oil. I

. Sulphur content-about 0.6%.

This last composition (IV) is the preferred starting material for preparing the polarvtype corrosion-preventing, lubricity-increasing agent of the present invention.

In certain of the above examples it is mentioned thefi; the final product has a "sulphur content (of) about 0.6%." This small content of sulphur-which is not believed to be present; in the form 01 a sulphuric acid derivative of the starting materialcan be removed by thoroughgoing washing and neutralization, and its presence in the final product is merely coincidental. one to allow the temperature of the H2804- containlng treatment mixture to rise substantially above 125 F., attack of the unsaponiflables by the sulphuric acid, with evolution of sulphur dioxide and with formation oi? sulphuric acid derivatives of the unsaponifiables, definitely would result: these latter would lower the yield of desired product, would be difflcult to remove and would cause ready emulsiflcation during neutralization and washing. On the other hand. it appears possible that some chemical change does take place by reason of the treatment with concentrated. sulphuric acid, since it is a fact that the product of the present process is diflerent In this connection it is noted that were from the extraction products obtained'by extracting the same starting material with such solvents as acetone, acetic acid, petroleum naphthe. and the like.

The process of the present invention is applicable also to the production of the polar type corrosion-inhibiting agents of the present invention from other petroleum oxidation products and derivatives thereof produced by the carrying out of the Burwell process of oxidation. Thus, the above sulphuric acid extraction treatment may be practiced on the following masses:

V. The total mass (i. e., crude reaction mixture) obtained by oxidizing a mixture of two parts by weight of crude scale wax and one part by weight of Sharples wax.

VI. A mixture of methyl esters of the acids recovered from the oxidation of a mixture of two parts by weight of crude scale wax and one part by weight of Sharples wax.

As will be appreciated, the above are illustrative rather than exhaustive of the invention. Thus, with reference to source material V, it will be appreciated that the crude reaction mixture (or "total mass) could have been that obtained by the oxidation, by the Burwell process of another petroleum material, e. g., crude scale and unoxidized petroleum hydrocarbons derived wax'alone, or Sharples wax alone, or a normally liquid fraction of petroleum, or a mixture of a normally liquid fraction of petroleum with crude scale wax and/or "Sharples wax. Likewise, with reference to source material VI above, it will be understood that the esterified mixture might consist of ethyl or butyl or other alkyl esters instead of the methyl esters; also that the esterified acids might have been produced by oxidation from a single fraction of petroleum (e. g., from crude scale wax, or from "Sharples wax, or from a normally liquid fraction of petroleum) or from difierent mixtures of petroleum fractions than that of the illustrative example.

The products of the present process are characterized by a strong attraction-for and ability to cling to metal surfaces on which latter they form adherent films adapted to protect the filmed metal against corrosion by atmospheric humidity, salt mist, salt spray, salt water immersion, etc.

Finally, and with particular reference to the accompanying flow chart, it should be stated that in the carrying out of the process of the present invention the unsaponifiables may, and normally would, be diluted with the low-boiling H2S04-resistant organic solvent in the same vessel that is used for treating them with sulphuric acid, with the result that the mixer vessel indicated in the flow. chart becomes unnecessary; also that the acid-soluble layer may, and normally would, be washed with water, diluted with amyl alcohol, and washed with alkali solution and with water in a single leadlined washer vessel, with the result that one from a petroleum fraction by the liquid-phase partial oxidation of the latter using an oxygencontaining gas as oxidizing means, which. comprises gradually adding to an agitated body of the mixture of oxygenated hydrocarbons at an initial elevated temperature of the order of 100 F., concentrated sulphuric acid in a total amount by weight at least equal to that of the oxygenated petroleum hydrocarbons content of said body while insuring thorough admixture and while maintaining the temperature of the resulting reaction mixture at not to exceed 125 F., allowing the reaction mixture to settle whereupon the same forms a supernatant non-aqueous layer containing concentrated sulphuric acid-insoluble components of the starting material and a subnatant acidic layer rich in oxygenated conipounds dissolved in concentrated sulphuric acid, separately recovering the subnatant acidic layer and removing free sulphuric acid from the latter.

3. Process of producing polar-type oil-soluble corrosion-preventing agents from mixtures of substantially unsaponifiable oxygenated predominately aliphatic and saturated hydrocarbons and unoxidized petroleum hydrocarbons derived from a petroleum fraction by the liquid-phase partial oxidation of the latter using an oxygen-containing gas as oxidizing means, which comprises dispersing amass of said mixture with a volatile inert organic solvent therefor whereby to produce a diluted freely liquid body of said mixture, gradually adding, to said diluted body of oxygenated hydrocarbons at an initial elevated temperature of the order of 100 F., concentrated sulphuric acid in a total amount by weight at least equal to that of the oxygenated petroleum hydrocarbons content of said body while insuring thorough admixture and while maintaining the temperature of the resulting reaction mixture at not to exceed 125 F., allowing the reaction mixture to settle whereupon the same forms a supersubstantially unsaponifiable oxygenated predomof the two "washer vessels indicated in the lower left hand column of the flow chart becomes unnecessary.

We claim:

1. Process of obtaining polar-type corrosion-- inately aliphatic and saturated hydrocarbons and unoxidized petroleum hydrocarbons derived from a petroleum fraction by the liquid-phase partial oxidation of the latter using an oxygen-containing gas as oxidizing means, which comprises dispersing a mass of said mixture with a volatile petroleum distillate of the type of petroleum naphtha whereby to produce a diluted freely liquid body of said mixture, gradually adding, to said diluted body of oxygenated hydrocarbons at an initial elevated temperature of the order of F., concentrated sulphuric acid in a total amount by weight at least equal to that of the oxygenated petroleum hydrocarbons content of said body while insuring thorough admixture and while maintaining the temperature of the resulting reaction mixture at not to exceed F., al-

. and unoxidized petroleum hydrocarbons derived from a petroleum fraction by the liquid-phase partial oxidation of the latter using an oxygencontaining gas as oxidizing means, which comprises dispersing a mass of said mixture with a volatile inert organic solvent therefor whereby to produce a diluted freely liquid body of said mixture, gradually adding; to said diluted body of -oxygenated hydrocarbons at an initial elevated temperature of the order of 100 F., concentrated sulphuric acid in a total amount by weight at least equal to that of the oxygenated petroleum hydrocarbons content of said body while insuring thorough admixture and while maintaining the temperature of the resulting reaction mixture at not to exceed 125 F., allowing the reaction mixture to settle whereupon the same forms a supernatant non-aqueous layer containing said solvent and concentrated'sulphuric acid-insoluble components of the starting material and a subnatant acidic layer rich in oxygenated compounds dissolved in concentrated sulphuric acid, separately recovering the subnatant acidic layer, washing the latter with water, and removing free sulphuric acid from the washed material.

6. Process of producing polar-type oil-soluble corrosion-preventing agents from mixtures of substantially unsaponifiabl oxygenated predominately aliphatic and saturated hydrocarbons and unoxidized petroleum hydrocarbons derived from a petroleum fraction by the liquid-phase partial oxidationof the latter using an oxygen-containing gas as oxidizing means, which comprises dispersing a mass of said mixture with a volatile inert organic solvent therefor whereby to produce a diluted freely liquid body of said mixture, gradually adding, to said diluted body of oxygenated hydrocarbons at an initial elevated temperature of the order of 100 F., concentrated sulphuric acid in a. total amount by weight at least equal to that of the ,oxygenated petroleum hydrocarbons content of said body while insuring thorough admixture and while maintaining the temperature of the resulting reaction mixture at not to exceed 125 F., allowing the reaction mixture to settle whereupon the same forms a supernatant non-aqueous layer containing said solvent and concentrated sulphuric acid-insoluble components of the starting material and a subnatant acidic layer rich in oxygenated compounds dissolved in concentrated sulphuric acid, separately recovering the subnatant acidic layer, washing the latter with water, adding to the washed material a substantial amount of amyl alcohol, washing the resulting amyl alcohol-containing mixture with an aqueous solution of an alkalineacting agent and repeatedly with water, and sub- Jecting the so treated and washed material to a distillation treatment whereby to remove amyl alcohol therefrom.

7. Process of producing polar-type oil-soluble corrosion-preventing agents from mixtures of substantially unsaponiflable oxygenated predominately aliphatic and saturated hydrocarbons and unoxidized petroleum hydrocarbons derived from a petroleum fraction by the liquid-phase partial oxidation of the latter using an oxygencontaining gas as oxidizing means, which comprises dispersing a mass of said mixture with a volatile inert organic solvent therefor whereby to produce a diluted ireely liquid body of said mixture, gradually adding, to said diluted body of oxygenated hydrocarbons at an initial elevated temperature of the order of 100 F., concentrated sulphuric acid in a total amount by weight at least equal to that of the oxygenated petroleum hydrocarbons content 01' said body while insuring thorough admixture and while maintaining the temperature of the resulting reaction mixture at not to exceed F., allowing the reaction mixture to settle whereupon the same forms a supernatant non-aqueous layer containing said solvent and concentrated sulphuric acidinsoluble components of the starting material and a subnatant acidic layer rich in oxygenated compounds dissolved in concentrated sulphuric acid, separately recovering the subnatant acidic layer, washing the latter with water, admixing the washed material with a substantial amount voi a volatile petroleum solvent of the type of petroleum naphtha, treating the resulting solvent-containing mixture, under agitation, with hydrated lime in an amount exceeding that required to react with any free sulphuric acid contained therein, filtering the resulting mixture to remove therefrom calcium sulphate and excess hydrated lime, and subjecting the filtrate to a distillation treatment whereby to remove volatile petroleum solvent therefrom.

8. The process defined in claim 1, in which the starting material from which the polar-type oilsoluble corrosion-preventing agent is produced is a mixture of unsaponiflable and non-acidic oxygenated petroleum hydrocarbons consisting mainly of aliphatic alcohols, aliphatic ketones, aliphatic keto-alcohols and neutral esters and lactones or high molecular weight aliphatic carboxylic acids, which oxygenated compounds are predominantly saturated and have been derived from a plurality of difierent petroleum fractions.

JAMES E. SHIELDS. EDWARD v. REILLY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain Jan. 4, 1938 

